AERIAL-PHOTOGRAPHY TECHNIQUES TO ESTIMATE POPULATIONS OF LAUGHING GULL NESTS IN JAMAICA BAY, NEW-YORK, 1992-1995

We evaluated aerial photography (full coverage, using fixed-wing aircr aft) and aerial video (transects, using helicopter) surveys to estimat e the population of Laughing Gull (Larus atricilla) nests in Jamaica B ay New York, during June 1992-1995. We counted 4,920 nests in the colo ny using aerial photography and estimated 5,367 nests using aerial vid eo in 1992. In 1993-1995, we respectively counted 5,691, 5,095, and 6, 126 nests in the colony using aerial photography, and estimated from g round plots that our counts differed from the actual number of nests b y means of -9% to 1%. Overall (1993-1995) correction factors (by which to multiply the aerial photography nest counts) to estimate the mean and 95% lower and upper CI range of the nest population were 1.04, 0.9 6 and 1.13, respectively. Ninety-seven percent of nests identified usi ng aerial photography or video had tl adult Laughing Gull present or w ithin 1 m of the nest. The aerial video survey was less expensive ($2, 100 United States currency) than the aerial photography survey ($4,000 ). The estimated cost of a total count of nests from the ground is $6, 700-$9,600. The aerial video survey provided an accurate estimate of t he number of nests. Full-coverage aerial photography also provided an accurate estimate of nests in addition to habitat, nest distribution a nd nest density data.